Meeting Abstract

P3.201  Friday, Jan. 6  Between-population variation in fluctuating asymmetry: testing the relative importance of spatial processes and ecological traits in the water-strider Aquarius chilensis BERTIN, A*; SAMPERTEGUI, S; RUIZ, V; FIGUEROA, R; GOUIN, N; Universidad de La Serena, Chile; Universidad de Concepcion, Chile; Universidad de Concepcion, Chile; Centro EULA, Concepcion, Chile; CEAZA, La Serena, Chile

Fluctuating asymmetry (FA), a measure of small non-directional departures from perfect symmetry in bilateral traits, is thought to reflect the level of genetic and environmental stress experienced by individuals or populations during development. While FA has been widely used as a bioindicator tool for environmental monitoring and conservation biology, our knowledge of the factors underlying its expression remains limited. In this study, we analyze the spatial structure of body shape asymmetry in the water-strider Aquarius chilensis across populations belonging to the same river basin and evaluate the importance of spatial processes and environmental characteristics (i.e. habitat and water characteristics, aquatic predators and parasitism) in producing between-population variation in FA. In both sexes, environmental and spatial processes explain more than 80% of the between population variation in FA. In females, a large fraction of this variation (i.e. 63%) is spatially structured with populations living near each other having more similar levels of FA than populations living further apart. According to variation partitioning analyses, both spatially-structured environmental factors and genetic relationships between populations may explain this phenomenon. In contrast, we did not evidence non-random spatial structure in males but found instead a predominant role of non-spatially structured environmental factors on FA levels. In sum both environmental and genetic factors may affect body shape FA in populations of A. chilensis but gender differences may occur, possibly due to alternative dispersion behaviors.